20171038661 has 4 divisors (see below), whose sum is σ = 20172755424. Its totient is φ = 20169321900.

The previous prime is 20171038631. The next prime is 20171038691. The reversal of 20171038661 is 16683017102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (20171038631) and next prime (20171038691).

It is a cyclic number.

It is not a de Polignac number, because 20171038661 - 2¹⁰ = 20171037637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20171038631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 840635 + ... + 864296.

It is an arithmetic number, because the mean of its divisors is an integer number (5043188856).

Almost surely, 2^20171038661 is an apocalyptic number.

It is an amenable number.

20171038661 is a deficient number, since it is larger than the sum of its proper divisors (1716763).

20171038661 is a wasteful number, since it uses less digits than its factorization.

20171038661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1716762.

The product of its (nonzero) digits is 12096, while the sum is 35.

The spelling of 20171038661 in words is "twenty billion, one hundred seventy-one million, thirty-eight thousand, six hundred sixty-one".